For a number of reasons, hydroponics has become an increasingly popular method for the propagation and cultivation of plants. Those employing hydroponics, for one, attain improved conservation and control of water, mineral nutrients, and supplements. This improved control can translate to enhanced vegetative and generative growth. A more recent development in the hydroponics industry is that of aeroponics, where the plant's roots are bare (without medium) within a chamber in which they are intermittently misted with nutrient solution.
With traditional hydroponics, the roots intercalate the growth media and are periodically submerged in water (as is done in, for instance, ‘ebb and flow hydroponic’ systems). With ‘deep water culture’ hydroponics, bare roots are continuously submerged in a vigorously aerated nutrient solution. Aeroponics is a method for propagating cuttings (colloquially known as cloning) which is favored by many in the hydroponics industry. These systems often attempt to automate the process of cloning by requiring less maintenance and attention as compared to propagating cuttings in media or soil. Moreover, such systems have become known as ‘cloning machines’, ‘aeroponic cloners’, cloners, etc. and are made by a number of manufacturers. Many cloning machines include a reservoir, tub, or growing chamber, a combination of pumps for air and/or water distribution; misters or sprayers for wetting the cuttings' stems; and lids which hold a plurality of cuttings. Various plant collars hold the cuttings in generally fixed relationships to the lids of these cloning systems.
However, heretofore-available plant collars suffer from a number of problems. For one thing, they cannot be cleaned or sterilized without shortening their service lives. Moreover, they tend to fail mechanically after several uses and can even introduce cleaning chemicals (which they have absorbed or adsorbed) into the plants that they hold. In addition, they tend to induce root growth at undesirable locations on the cloned plants thereby resulting in subsequent difficulties when the clones are transplanted. In the alternative, or in addition, the roots can grow into heretofore-available plant collars leading to their breakage when mature plants are subsequently removed from the cloning machines. Furthermore, they harbor water leading to the growth of fungus and/or other pathogens that can harm the health of the plants or even kill them.